Thursday, April 19, 2012

Bottom Trawling


            Bottom trawling is a destructive fishing practice that is carried out by scraping a trawl net across the sea floor to pick up desirable fish. While bottom trawling yields many fish fit for the table, far more harm is done than good.  Bottom trawling picks up tons of other, unwanted organisms and plants, from seaweed to coral.  It is indiscriminate in its selection, and can destroy the ecosystem of the sea floor.  Bycatch can account for 90% of a trawl's total catch.  Since weights are needed to hold the net at the bottom of the sea, large areas of benthic habitats can be destroyed while trawling.

Marine Conservation Biology Institute. Destructive Fishing. Retrieved from             http://www.mcbi.org/what/destructive_fishing.htm
            People are eating down the food web, which means that they are eating more bottom-dwelling creatures.  This causes more need for bottom trawling, which churns up sediment and kills bottom dwelling fish, invertebrates, and corals.  More dead zones appear. Fisheries further north have been depleted, so companies are moving south to catch fish, destroying even more ecosystems.
Pauly, Daniel (9 October 2007).  Fisheries and Global Warming: Impacts on Marine Ecosystems             and Food Security.  Retrieved From http://mitworld.mit.edu/video/501/
            Bottom trawling reduces habitat complexity.  In areas that don't get much natural disturbance from waves or tidal currents, like the deep sea, are more affected by bottom trawling than areas that do.  Trawling can collapse ecosystems and hurt the populations of rare species.  Even if bottom trawling is stopped, it is not there is no guarantee that the areas affected by bottom trawling will return to their pre-trawl ecosystems.  It also homogenizes the sea floor, which decreases habitat complexity, reduces the range of some species, messes with reproductive rates, and fragments habitats and populations. 
            A possible solution to the bottom trawling problem are closing areas to fishing to protect marine organisms and their habitats.  Another solution is to modify fishing gear to minimize contact with the sea floor.
Alaska Marine Conservation Council (2006).  Impacts of Bottom Trawling. Retrieved from             http://www.akmarine.org/our-work/conserve-fisheries-marine-life/impacts-of-bottom-            trawling

No comments:

Post a Comment